MMCI: Re-design of power management

Cards are kept powered until we enter suspend mode.

Since the cards are still powered after a "disable" has
been done, the disable/enable function do only save/restore
the PL180 register settings. Earlier the card needed to be
re-initialized as well. This minimizes the access latency
to the card to below 0 ms. Earlier the worst case seen with
a certain SD card was around 1000 ms.

In the suspend function the power to the card is cut to save
current. This also means the cards must be re-initialized
when doing resume. Unfortunately the resume time is then
increased since the re-initialization of a SD card might
as stated take up to 1000 ms in worst case.

ST-Ericsson ID: 327273, 318306

Change-Id: Ifefc7a140dfa78509ee9e808863671ce812b4f20
Signed-off-by: Ulf Hansson <ulf.hansson@stericsson.com>
Reviewed-on: http://gerrit.lud.stericsson.com/gerrit/19662
Reviewed-by: Stefan NILSSON9 <stefan.xk.nilsson@stericsson.com>
Reviewed-by: Joakim AXELSSON <joakim.axelsson@stericsson.com>
Reviewed-by: Sebastian RASMUSSEN <sebastian.rasmussen@stericsson.com>

2 files changed, 58 insertions, 62 deletions

diff --git a/drivers/mmc/host/mmci.c b/drivers/mmc/host/mmci.c
index 25dc5df1ca7..dd1c21c1ed2 100644
--- a/drivers/mmc/host/mmci.c
+++ b/drivers/mmc/host/mmci.c
@@ -1265,9 +1265,9 @@ static int mmci_get_cd(struct mmc_host *mmc)
 #ifdef CONFIG_PM
 static int mmci_enable(struct mmc_host *mmc)
 {
+	unsigned long flags;
 	struct mmci_host *host = mmc_priv(mmc);
 	int ret = 0;
-	unsigned int mask;
 
 	clk_enable(host->clk);
 	if (host->vcc) {
@@ -1287,11 +1287,7 @@ static int mmci_enable(struct mmc_host *mmc)
 	if (host->plat->wakeup_handler)
 		host->plat->wakeup_handler(host->mmc, true);
 
-	/* Enable IRQ */
-	mask = MCI_IRQENABLE;
-	/* Don't use the datablockend flag if it's broken */
-	if (host->variant->broken_blockend)
-		mask &= ~MCI_DATABLOCKEND;
+	spin_lock_irqsave(&host->lock, flags);
 
 	if (host->variant->sdio &&
 		host->mmc->card &&
@@ -1304,9 +1300,12 @@ static int mmci_enable(struct mmc_host *mmc)
 		writel(MCI_ST_DPSM_SDIOEN, host->base + MMCIDATACTRL);
 	}
 
-	writel(mask, host->base + MMCIMASK0);
+	/* Restore registers for POWER, CLOCK and IRQMASK0 */
+	writel(host->irqmask0_reg, host->base + MMCIMASK0);
+	writel(host->pwr_reg, host->base + MMCIPOWER);
+	writel(host->clk_reg, host->base + MMCICLOCK);
 
-	mmc_power_restore_host(host->mmc);
+	spin_unlock_irqrestore(&host->lock, flags);
 
 	return ret;
 }
@@ -1316,9 +1315,6 @@ static int mmci_disable(struct mmc_host *mmc, int lazy)
 	unsigned long flags;
 	struct mmci_host *host = mmc_priv(mmc);
 
-	if (lazy && !mmc_try_claim_host(host->mmc))
-		return host->plat->disable;
-
 	/*
 	 * To be able to handle specific shutdown scenarios for each host,
 	 * the following function shall be implemented.
@@ -1326,8 +1322,12 @@ static int mmci_disable(struct mmc_host *mmc, int lazy)
 	if (host->plat->wakeup_handler)
 		host->plat->wakeup_handler(host->mmc, false);
 
-	/* Take actions specific for power save. */
-	mmc_power_save_host(host->mmc);
+	spin_lock_irqsave(&host->lock, flags);
+
+	/* Save registers for POWER, CLOCK and IRQMASK0 */
+	host->irqmask0_reg = readl(host->base + MMCIMASK0);
+	host->pwr_reg = readl(host->base + MMCIPOWER);
+	host->clk_reg = readl(host->base + MMCICLOCK);
 
 	/*
 	 * Make sure we do not get any interrupts when we disabled the
@@ -1335,20 +1335,15 @@ static int mmci_disable(struct mmc_host *mmc, int lazy)
 	 * interrupts, since they may occur even without any active
 	 * request handling ongoing.
 	 */
-	spin_lock_irqsave(&host->lock, flags);
 	writel(0, host->base + MMCIMASK0);
+
 	spin_unlock_irqrestore(&host->lock, flags);
 
 	clk_disable(host->clk);
 	if (host->vcc) {
 		regulator_disable(host->vcc);
-		dev_dbg(mmc_dev(host->mmc), "disabled regulator %s\n",
-			host->plat->vcc);
 	}
 
-	if (lazy)
-		mmc_release_host(host->mmc);
-
 	return 0;
 }
 #else
@@ -1426,6 +1421,10 @@ static int __devinit mmci_probe(struct amba_device *dev, struct amba_id *id)
 	host->gpio_cd = -ENOSYS;
 	host->gpio_cd_irq = -1;
 
+	host->irqmask0_reg = 0;
+	host->pwr_reg = 0;
+	host->clk_reg = 0;
+
 	host->hw_designer = amba_manf(dev);
 	host->hw_revision = amba_rev(dev);
 	dev_dbg(mmc_dev(mmc), "designer ID = 0x%02x\n", host->hw_designer);
@@ -1438,10 +1437,6 @@ static int __devinit mmci_probe(struct amba_device *dev, struct amba_id *id)
 		goto host_free;
 	}
 
-	ret = clk_enable(host->clk);
-	if (ret)
-		goto clk_free;
-
 	host->mclk = clk_get_rate(host->clk);
 	/*
 	 * According to the spec, mclk is max 100 MHz,
@@ -1451,7 +1446,7 @@ static int __devinit mmci_probe(struct amba_device *dev, struct amba_id *id)
 	if (host->mclk > 100000000) {
 		ret = clk_set_rate(host->clk, 100000000);
 		if (ret < 0)
-			goto clk_disable;
+			goto clk_free;
 		host->mclk = clk_get_rate(host->clk);
 		dev_dbg(mmc_dev(mmc), "eventual mclk rate: %u Hz\n",
 			host->mclk);
@@ -1460,7 +1455,7 @@ static int __devinit mmci_probe(struct amba_device *dev, struct amba_id *id)
 	host->base = ioremap(dev->res.start, resource_size(&dev->res));
 	if (!host->base) {
 		ret = -ENOMEM;
-		goto clk_disable;
+		goto clk_free;
 	}
 
 	mmc->ops = &mmci_ops;
@@ -1485,14 +1480,9 @@ static int __devinit mmci_probe(struct amba_device *dev, struct amba_id *id)
 		ret = IS_ERR(host->vcc);
 		if (ret) {
 			host->vcc = NULL;
-			goto clk_disable;
+			goto clk_free;
 		}
-
-		ret = regulator_enable(host->vcc);
-		if (ret)
-			goto vcc_free;
-
-		dev_dbg(mmc_dev(host->mmc), "enabled regulator %s\n",
+		dev_dbg(mmc_dev(host->mmc), "fetched regulator %s\n",
 			plat->vcc);
 	}
 
@@ -1503,7 +1493,7 @@ static int __devinit mmci_probe(struct amba_device *dev, struct amba_id *id)
 		ret = IS_ERR(host->vcard);
 		if (ret) {
 			host->vcard = NULL;
-			goto vcc_disable;
+			goto vcc_free;
 		}
 		dev_dbg(mmc_dev(host->mmc), "fetched regulator %s\n",
 			plat->vcard);
@@ -1519,13 +1509,19 @@ static int __devinit mmci_probe(struct amba_device *dev, struct amba_id *id)
 				 "Provided ocr_mask/setpower will not be used "
 				 "(using regulator instead)\n");
 		}
-	}
 
-	/* Use platform data if no regulator for vcard is used */
-	if (host->vcard == NULL)
+	} else {
+		/* Use platform data if no regulator for vcard is used */
 		mmc->ocr_avail = plat->ocr_mask;
+	}
+
+	/* Use platform capabilities */
 	mmc->caps = plat->capabilities;
 
+	/* Set disable timeout if supported */
+	if (mmc->caps & MMC_CAP_DISABLE)
+		mmc_set_disable_delay(mmc, plat->disable);
+
 	/* Use platform bus_resume_flags */
 	mmc->bus_resume_flags = plat->bus_resume_flags;
 
@@ -1562,10 +1558,6 @@ static int __devinit mmci_probe(struct amba_device *dev, struct amba_id *id)
 
 	spin_lock_init(&host->lock);
 
-	writel(0, host->base + MMCIMASK0);
-	writel(0, host->base + MMCIMASK1);
-	writel(0xfff, host->base + MMCICLEAR);
-
 	if (gpio_is_valid(plat->gpio_cd)) {
 		ret = gpio_request(plat->gpio_cd, DRIVER_NAME " (cd)");
 		if (ret == 0)
@@ -1611,7 +1603,10 @@ static int __devinit mmci_probe(struct amba_device *dev, struct amba_id *id)
 			goto irq0_free;
 	}
 
-	writel(MCI_IRQENABLE, host->base + MMCIMASK0);
+	/* Prepare IRQMASK0 */
+	host->irqmask0_reg = MCI_IRQENABLE;
+	if (host->variant->broken_blockend)
+		host->irqmask0_reg &= ~MCI_DATABLOCKEND;
 
 	amba_set_drvdata(dev, mmc);
 
@@ -1623,16 +1618,6 @@ static int __devinit mmci_probe(struct amba_device *dev, struct amba_id *id)
 		 amba_config(dev), (unsigned long long)dev->res.start);
 	dev_info(&dev->dev, "IRQ %d, %d (pio)\n", dev->irq[0], dev->irq[1]);
 
-	/* Disable clock and set disable delay if supported */
-	if (mmc->caps & MMC_CAP_DISABLE) {
-		mmc_set_disable_delay(mmc, plat->disable);
-		clk_disable(host->clk);
-	}
-
-	/* Disable host regulator if supported */
-	if (host->vcc)
-		regulator_disable(host->vcc);
-
 	/* Ugly hack for u8500_sdio_detect_card, to be removed soon. */
 	sdio_host_ptr = host;
 
@@ -1651,14 +1636,9 @@ static int __devinit mmci_probe(struct amba_device *dev, struct amba_id *id)
 		gpio_free(host->gpio_cd);
  err_gpio_cd:
 	iounmap(host->base);
- vcc_disable:
-	if (host->vcc)
-		regulator_disable(host->vcc);
  vcc_free:
 	if (host->vcc)
 		regulator_put(host->vcc);
- clk_disable:
-	clk_disable(host->clk);
  clk_free:
 	clk_put(host->clk);
  host_free:
@@ -1730,22 +1710,30 @@ static int mmci_suspend(struct amba_device *dev, pm_message_t state)
 	int ret = 0;
 
 	if (mmc) {
-
 		/*
 		 * The host must be claimed to prevent request handling etc.
 		 * Also make sure to not sleep, since we must return with a
 		 * response quite quickly.
 		 */
 		if (mmc_try_claim_host(mmc)) {
-			if (mmc->enabled) {
+			struct mmci_host *host = mmc_priv(mmc);
 
+			if (mmc->enabled) {
 				/*
 				 * Do not suspend if the host has not been
 				 * disabled.
 				 */
 				mmc_do_release_host(mmc);
 				ret = -EBUSY;
+			} else {
+				/* Cut the power to the card to save current. */
+				mmc_host_enable(mmc);
+				mmc_power_save_host(mmc);
+				mmc_host_disable(mmc);
+				host->pwr_reg = 0;
+				host->clk_reg = 0;
 			}
+
 		} else {
 			/*
 			 * We did not manage to claim the host, thus someone
@@ -1763,12 +1751,15 @@ static int mmci_resume(struct amba_device *dev)
 	struct mmc_host *mmc = amba_get_drvdata(dev);
 
 	if (mmc) {
-		/*
-		 * We expect the host to be claimed.
-		 * Release the host to provide access to it again.
-		 */
+		/* We expect the host to be claimed. */
 		WARN_ON(!mmc->claimed);
 
+		/* Restore power and re-initialize the card. */
+		mmc_host_enable(mmc);
+		mmc_power_restore_host(mmc);
+		mmc_host_disable(mmc);
+
+		/* Release the host to provide access to it again. */
 		mmc_do_release_host(mmc);
 	}
 
diff --git a/drivers/mmc/host/mmci.h b/drivers/mmc/host/mmci.h
index 73e9cff3333..bd842430696 100644
--- a/drivers/mmc/host/mmci.h
+++ b/drivers/mmc/host/mmci.h
@@ -191,6 +191,11 @@ struct mmci_host {
 	bool			last_blockend;
 	bool			dataend;
 
+	/* register cache */
+	unsigned int		irqmask0_reg;
+	unsigned int		pwr_reg;
+	unsigned int		clk_reg;
+
 	/* pio stuff */
 	struct sg_mapping_iter	sg_miter;
 	unsigned int		size;